MK5 Golf GTI
All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: vRS Carl on February 23, 2010, 05:09:54 pm
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Ok before i start i want to stress that this post is My Personal Opinion :smiley: :smiley:
Currently i am thinking of upping the power on my car. Now wether this is K04 or Big Turbo kit i have yet to decide.
A number of people keep telling me though "oooh your gonna need bigger brakes if you start doing that".
What i really want to know though is Why do i need bigger brakes?
My thinking is this -
My car is a Skoda Octavia vRS. 200bhp as Standard and a 149mph top speed buy the book. So the car has 150mph Brakes on it anyway.
Now as i don't take my car on a track the only thing i have done brake wise is uprate the pads to DS2500's at the front. This has provided me with a bit more bite etc however i don't find myself braking later into corners etc.
It doesn't matter how good your brakes are your car will only go around any corner at a given speed. After that it is going to under/oversteer depending on the Corner/Car & Chassis.
Ok i agree having better brakes means i can brake later going into a corner. But as i have said i don't race my car on a track so this feature is of little use.
I have also been taught how to drive a car at high speed and control it so don't really have a problem when it comes to cornering or stopping etc.
I am also a firm believer that you could have the best brakes in the world but if you have Sh!te tyres then they aren't much use. To me it makes much more sense to have decent brakes (which the car has) and decent tyres. Surely this gives the same effect as having a big brake kit on and not so decent tyres.
My other thinking is no matter what i do power wise the car will still be the same weight etc so if (for example) i am trying to slow from 130Mph. I may have got there quicker but the Velocity & Mass of the car are still the same so my OEM brakes coupled with DS2500's are more than capable.
AM i being really stupid here (or in my case trying to save money and spend it on a Diff instead :laugh:)
Or because i don't take the car on the track and i don't drive like i stole it everywhere i am actually making sense?
Thoughts/comments good or bad welcome but please be constructive
Cheers
Carl :happy2:
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312s are fine then.
Just spec the fluid and pads accordingly so should you ever seriously need them, they'll have much better capability to deal with it.
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small brakes heat up and fade , due to the size and fluid you run . plus the oe calipers are single pot sliders so not a massive amount of force is applied , correct tyres is where things happen . im a firm beliver in tyres , you could spend 2k on coilover arbs etc , but if you spend 50 quid on hedgemaster 3000 (joke tyres) then you will be in the hedge backwards .
the best thing for you to do is to buy some r32 calipers and good discs with some ds2500 / braided hoses / 5.1 dot fluid .
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TBH I do agree with Gill,
312s might serve you well for years, but for what R32 stoppers cost and the improvement they make, it's a no brainer.
You don't need a £xxxx BBK for sure.
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audi RS4 B7 360mm twin pots can be had for £750 all in if you speak to the man in the know........he'll be along shortly. they'll be substantially stronger than R32 brakes for sure
they were mine until i decided to flog the vRS for something quicker
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agree with what others have said.
your choice is really spend ££ for R32 (+ rear to balance it?) or ££££ on a BBK
the key point for me was that the std 312mm arent '150mph' brakes in the first place.
marginal for 200bhp maybe but higher definitely not.
even without crazy driving or track, one good stop from reasonable speed and they would fade.
I guess its the opposite of the headroom tuning ability for the K04 cars :signLOL:
there are also additional issues like improved pedal feel.
I intend to writeup on my build thread but there are also downside to R32 setup (increased unsprung weight), and prob more balanced with matched rears.
Top Cats RS4 (old version) brake setup is well nice too for a bit more £££
Im very happy with mine, but Im looking to offset the weight with TT arms/hubs / new wheels etc
in summary I reckon you should consider your options :happy2:
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I can only echo what the others have said and would go as far as saying my R32/Cupra R fronts is one of the best things I did to my car.
They can be a bit grabby at times though but their ability easily outweighs any negatives. :happy2:
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just to add to my post , i have used my 312s on track . on uk tracks they were fine on cold sessions (nov track days) done a whole day at donny , but at the ring mine were dead at adneu . and at combe in summer months they were tired after around 5 laps .
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my 312s with uprated pads were absolutely shagged after 3 laps of the ring. by far the weakest point on the car
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Something I failed to add was that I only have 17" wheels so I don't want to be forking out for 18" wheels aswell just to fit an R32 brake kit.
I reckon I could get the same from the DS2500's, maybe better discs, braided hoses and decent tyres.
As I said I don't go on tracks with the car and don't drive it like I stole it.
Thanks for all the input guys. Keep it coming
Carl :happy2:
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well do not fear carl the audi b7 360mm twin pots fit under 17" wheels. Topp cat has done it on here already, and they will only cost you a further 150-200 over the R32 setup and weill be hugely stronger
http://www.mk5golfgti.co.uk/forum/index.php/topic,36.195.html
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R32 stoppers go under 17"s too :happy2:
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Is that a definate as JKM say that they only fit under 18's
Carl :happy2:
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Yeah, I've seen an R32 with 17" Monzas on and German winter steels are only 17" too.
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this has been covered several times before, yes r32 stoppers fit under 17"
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi715.photobucket.com%2Falbums%2Fww160%2Fjakethemoss%2FIMG_4889-1.jpg&hash=c4b401d3bac717471ee4c8f7d3cbf05e8f82ee3d)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi715.photobucket.com%2Falbums%2Fww160%2Fjakethemoss%2FIMG_4890-1.jpg&hash=4dacd55a3129d7be9f0b1635b1247db0bf4214eb)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi715.photobucket.com%2Falbums%2Fww160%2Fjakethemoss%2FIMG_4908.jpg&hash=1cab3934e41d6378db97ca014e408be5717b1acf)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fi715.photobucket.com%2Falbums%2Fww160%2Fjakethemoss%2FIMG_4911.jpg&hash=e5ca8de32602fc3d2c38d4853c72391cc19871c0)
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360mm discs go under 17s.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ftomashandmilly%2Fpics_since_clubsports%2FImage068-1.jpg&hash=629d4fa983a10f82b9d965fc54845e0edd2fa236)
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Not much room left there :signLOL:
Hmmm that changes things a bit then.
Will have to speak to JKM about that.
Cheers Folks keep it coming
Carl :happy2:
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As ever its all about balance, if you are going to improve/mod the engine then good sense would suggest you need to do something with the other "systems" even if that means just having them checked over!
The problem with 312's is not disc size nor pad size, its the combination and interaction of the pad/disc/caliper that ultimately leads to problems. 312 calipers are thin walled with a large surface area which leads to heat build up, OEM pads depending on supplier are normally classified as being suitable for the lower range of temps that regulation 90 provides for, 312 discs are 25mm thick which dont have much mass to absorb much heat. The general rule of thumb for disc thickness is that for every 10% increase in disc thickness you can get 40% more energy into the disc for a given temp increase.
Having spouted all that BS, it sounds like you've hit the nail on the head in that the shoe needs to fit the foot and you need a BBK like you need a hole in the head.
Might be an idea to budget for a S3/R32 setup more for peace of mind than outright performance.
The B5 RS4 setup is relatively good value, its Iron has large discs which does increase brake torque substantially and is a great solution for those with LM style lipped or multi piece wheels which dont lend themselves to bigger calipers.
Compare the 312's on your golf to say a "standard" 996 Carrera 2
Porsche Disc size 318mm (Dont forget diameter counts for nothing its radius that matters)
Porsche Pad is smaller (bigger pads dont make you stop better)
So why do Porsche stop very well?......its all about balance, they have multi piston rear calipers as well as fronts which have better "feel" characteristics than single piston setups liek your 312's. Single piston setups are cheap to produce and straightforward to make effective they dont lend themselves to good comms when approaching the limit all of which has no interest to the OP!
Found myself a guinea pig for Boxster fronts on Mk5 312's so we'll run em for 1k miles and report back, it worked well on the Mk4 with the same hydraulic numbers and should work better on the Mk5 as the rears being bigger will give a little more rear bias.
Should be a lightweight ally caliper solution without going to the frankly podgy 345mm disc with good clubman pad options for road and track that'll fit under 17's. Couple of months away though. Using 312's discs however it wont suit the biggest is best brigade
Back to the OP good for you for not getting roped into the BBK treadmill but imho you'll need to do something with the fronts because if the power is there and the road looks like fun you'll use it and might just find yourself wishing you had made some provision for some slightly better stoppers
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Thanks for all the input guys.
Having read through this it's kinda made my made up that you lot know absolutley f*ck all and just want me to spend my hard earned cash :laugh: :laugh: :laugh:
Just kidding. Been some excellent advice there and i will now be on the look out for a S3/R32/Cupra brake kit. Would prefer the S3 kit as it has black calipers (Who has red as i would actually prefer to keep the OEM look) but if any set comes along at a good price then i think i will be purchasing :smiley: :smiley:
Can this be fitted by myself (bear in mind i am not very mechanically minded but have done a fair bit of stuff on my car myself) if so what tools will i need and are the Brakes just a straight swap or do they have to be barstewardsised in any way.
Again thanks for all the input and good advice
Carl :happy2:
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they are a straight swap and could be done in about a hour and a half inc bleeding them and stopping for a fag and coffee
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Bit less for me then as i don't smoke (except in bed :wink:)
Carl :happy2:
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Carl I have been running my KO4 for 10k now and on 312's. They are ok for road use. There is not much point changing them unless you go on track or the ring..
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Thanks Mickey.
I have been thinking about it more recently and just feel that the DS2500's & 312mm Discs will be fine for Road use as i don't drive like i Stole it.
Carl :happy2:
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I'm also using the R32 front brakes for quite some time and tracked them at Nurburgring last year. The pedal feel is much better that the OEM 312s but probably the cold stopping distances are about the same. The problem is when you start heating them. I have a very nice mountain road of about 40kms (somehow similar to Stelvio pass). I've been there with my OEM brakes and they never lasted more than 10kms under very hard driving. Black smoke came out, pedal became stiff...With the uprated R32 brakes + DS2500 pads, I finished the 40kms and 3 consecutive laps on Nurburgring with 0 fade. Knowing I do have quite a lot of power/torque as compared to stock, I would go even higher with the brakes but I'm afraid a small improvement over the R32 brakes would triple the costs for the brakes. Anyone tested the RS4 fronts against the R32 on mk5 GTI ? I would be curious about the differences in fade, stopping power and handling (don't know how heavy RS4 ones are compared to R32 ones). Soemthing interesting for me though was to find out that the discs from VwRacing brakes were about 2 times lighter than my R32 ones wich should mean something for handling. When my friend TEFF (present here on the forums) will install them, I'll have a run in his car and report back with the differences !
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I'm also using the R32 front brakes for quite some time and tracked them at Nurburgring last year. The pedal feel is much better that the OEM 312s but probably the cold stopping distances are about the same. The problem is when you start heating them. I have a very nice mountain road of about 40kms (somehow similar to Stelvio pass). I've been there with my OEM brakes and they never lasted more than 10kms under very hard driving. Black smoke came out, pedal became stiff...With the uprated R32 brakes + DS2500 pads, I finished the 40kms and 3 consecutive laps on Nurburgring with 0 fade. Knowing I do have quite a lot of power/torque as compared to stock, I would go even higher with the brakes but I'm afraid a small improvement over the R32 brakes would triple the costs for the brakes. Anyone tested the RS4 fronts against the R32 on mk5 GTI ? I would be curious about the differences in fade, stopping power and handling (don't know how heavy RS4 ones are compared to R32 ones). Soemthing interesting for me though was to find out that the discs from VwRacing brakes were about 2 times lighter than my R32 ones wich should mean something for handling. When my friend TEFF (present here on the forums) will install them, I'll have a run in his car and report back with the differences !
The RS4 discs are a fair bit lighter than the R32 ones even though they are a bigger. I held them side by side and there was a clear difference in weight. The RS4 discs have alu bells. :happy2:
I havn't tested them enough for fade yet due to our bleak winter but the actual stopping power is night and day better than the standard GTI brakes. :love:
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What would be a propper pad to use on the Ring with these RS4 calipers ? I'm talking of course about pads that can also be driven on the way to the track (public road) without taking a ticket for squealing or hitting the car in front of you because they haven't been warmed enough ! :) . I would be also very curious about the difference in weight between R32 fronts and RS4 B5 fronts and how will this affect handling !
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Fuscobal, you should consider the S3 hubs:
http://www.mk5golfgti.co.uk/forum/index.php/topic,12575.0.html
http://www.mk5golfgti.co.uk/forum/index.php/topic,12348.0.html
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What would be a propper pad to use on the Ring with these RS4 calipers ? I'm talking of course about pads that can also be driven on the way to the track (public road) without taking a ticket for squealing or hitting the car in front of you because they haven't been warmed enough ! :) . I would be also very curious about the difference in weight between R32 fronts and RS4 B5 fronts and how will this affect handling !
This should help. :happy2:
Very interesting set of brakes these, with Toms wheels we often joked about the BBK picking us as opposed to us picking the BBK. I'm really interested in how they do on the track as the original RS4 purists always rated them well especially when used with the correct pads.
Audi did a competition package for the RS4 which comprised drilled discs and "competition" pads (which are Pagid RS29's) see pic
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fae279%2FDelta-Performance%2F657RS4_sport_brakes.jpg&hash=265f67bff4f2189815dc8cc9d29a21efc612f1df)
There was a huge gap betweenthe 2001 B5 RS4 and the 2006 8 pot equipped RS4 B7 with little in the way of an upgrade path for B5 owners so the competion package was the way to go, theres been a plenty of track slagging in 1400kg RS4s on these brakes many of which were running a 2.7Bi turbo V6 doing a reliable 500BHP.
Anyway point of my rambling is that they come up on ebay fairly regularly and even if you have to replace the discs, then its potentially a great track proven "clubman" brake setup for potentially way way less than 4 figures and thats even with Pagid RS pads included in that ball park price!
Probably the only 360mm setup that goes under 17's as well!!!
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Fuscobal, you should consider the S3 hubs:
http://www.mk5golfgti.co.uk/forum/index.php/topic,12575.0.html
http://www.mk5golfgti.co.uk/forum/index.php/topic,12348.0.html
Wow, this is the first time I hear about these. Are they lighter than the GTI ones ? Any other advantage ?
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if you go for the lower arms also which is also alloy you get a bit of camber adjust also
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I've searched for RS4 B5 brakes on ebay and the prices seem pretty high, not to mention I couldn't find the "Audi exclusive" lighter drilled discs but only the plain ones ! What would be a correct price for such a kit on second-hand ? (calipers, carriers, discs, pads, bolts, lines, splash shields...)
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k, just found some RS4 B5 brakes with standard discs (not drilled) and pad. The set has about 10.000km wich is not much. Is the caliper bolt-on to mk5 with no other mod ? (like custom carrier or something)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg532.imageshack.us%2Fimg532%2F4875%2Fdisa3.jpg&hash=5091989174a7a0aa2876c2397716e395d717cc1a)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg715.imageshack.us%2Fimg715%2F1296%2Fdisa2.jpg&hash=fd0e8d8af53e7ac07191d83f00ce3e00aae49ce7)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg692.imageshack.us%2Fimg692%2F9669%2Fdisa1.jpg&hash=91fde9799be65d43a7756aa7d761f58ae28907a6)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg502.imageshack.us%2Fimg502%2F4731%2Fcala4.jpg&hash=3f175d3a8aa5e2ec7a09582a2add3b5468391340)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg101.imageshack.us%2Fimg101%2F6199%2Fcala3.jpg&hash=bafa984c1c4ddb7784c76bdb16279d589aa2e356)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg683.imageshack.us%2Fimg683%2F4977%2Fcala2.jpg&hash=640dc190dfabba4c13c81d883dc7f624133cf875)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fimg502.imageshack.us%2Fimg502%2F4731%2Fcala4.jpg&hash=3f175d3a8aa5e2ec7a09582a2add3b5468391340)
What do you think about 450Euro for this setup ?
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I will direct DaveB to this thread when he next appears, he is the chap who got me the kit and made it fit.
I will try and explain the fitting but will probably just confuse myself and you. When fitting the Audi discs there is nothing to hold it onto the hub other than the wheel bolts. I wasn't happy about this so he came up with the idea of a screw that goes through the disc into the hub and a shim that keeps the disc centred, it was a pretty simple fix But Dave would be able to explain it better than me. :happy2:
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Ok, thanks. I sent him some PMs myself but he doesn't seem to be around in the last days !
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Sorry been away with the smelly cheese eating surrender monkeys.
Fuscobal
If you're looking at the B5 RS4 kit over on audi-sport.net get them bought quick - Im seriously thinking about buying them myself.
You'll need conversion shims, 3mm longer carrier mounting bolts (OEM), spiggot rings and expanding collets for mounting the discs. Its sound engineering that we were lucky enough to have another look at recently to check it over again and it works really well.
The whole kit complete for mounting is £100........ each item is machined individually.
You'll also need some different hoses - £45
And some Mk5 R32 disc shields - £10
Get them bought mate
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Hello Dave,
I've actually found these on ebay, not audi-sport.net (don't have an account there and don't know if it's the same seller). Dave, can you also please respond to my PM regarding the R32 rears ? :)
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audi RS4 B7 360mm twin pots can be had for £750 all in if you speak to the man in the know........he'll be along shortly. they'll be substantially stronger than R32 brakes for sure
Huh - I think you may have your wires crossed. The B7 RS4 (with the standard 360mm iron discs) have 8 pot calipers up front, and single pot rears. The B5 RS4 also had 8 pots up front.
The only Audis I can think of with those 2 pot calipers was the B5 S4.
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Hi Sean
B5 RS4 had the same caliper as the MK4 R32 2 x 43mm pistons, if you look at page 2 on here you'll see a promo Audi pic for the competition pads and discs that are available and shown on ETKA. You paid double and got drilled discs instead of plain and some thinly disguised RS19/29's which had an Audi part number.
RS4's ---- B7 8 pots 365mm disc - B5 2 pots 360mm disc
Its a handy setup for those that need some more stopping but have restrictive rimmage that wont allow opposed piston calipers.
B5 S4 had two pot lucas calipers on 323mm discs from memory, you'll remember these were the ones with 4 "triangular" style pads per corner, you'll also probably remember that they weigh a bloody ton and after 2003 they changed it to a iron housing and an ali frame to slim them down a bit
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Hi Sean
B5 RS4 had the same caliper as the MK4 R32 2 x 43mm pistons, if you look at page 2 on here you'll see a promo Audi pic for the competition pads and discs that are available and shown on ETKA. You paid double and got drilled discs instead of plain and some thinly disguised RS19/29's which had an Audi part number.
RS4's ---- B7 8 pots 365mm disc - B5 2 pots 360mm disc
Ahhhh - me getting confused. It was the C5 RS6 with the 8 pot Brembos. Maybe those were retro-fitted to B5 RS4s????
Its a handy setup for those that need some more stopping but have restrictive rimmage that wont allow opposed piston calipers.
Righty :happy2: So who made those two-poters? And how rigid are the sliding pins? And will they fit under 18" Monza IIs ? :wink:
B5 S4 had two pot lucas calipers on 323mm discs from memory, you'll remember these were the ones with 4 "triangular" style pads per corner, you'll also probably remember that they weigh a bloody ton and after 2003 they changed it to a iron housing and an ali frame to slim them down a bit
That's right - Lucas calipers - not very popular design! :sick: